The present invention relates generally to the field of mobile and handheld electronic devices. More specifically, embodiments of the present invention relate to a reduced keyboard system and method that is useful for all types of electronic devices that employ text input.
In the specification and the claims, which follow herein the terms “keyboard” and “keypad” are intended to mean a grouping of individual keys, as known in the art, used primarily for text input. “Reduced keyboard” and/or “reduced keypad”, as used hereinbelow in the specification and the claims, are intended to mean a keyboard and/or a keypad having reduced dimensions, such as found in, but not limited to, handheld electronic devices. “Character”, as used hereinbelow in the specification and the claims, is intended to mean generally a symbol or a letter—in contradistinction to a digit. When used in the context of describing a word (such as, but not limited to: “character in a word”) the intention is a letter in the alphabet (in an alphabet-based language) or a component symbol (in a language having symbols which make up words).
Text entry for mobile and handheld devices represents a field that is developing at a very fast pace. With the continuously decreasing size of PDA's and similar devices, a major challenge of text entry has been the need for a compact keyboard that does not compromise the input speed or accuracy of the system. Typically, devices that have built-in hardware keyboards do not allow for fast text input, since individual keys on the keyboard are very small. Hand-writing recognition systems are highly dependent on the handwriting input quality and do not provide the desired level of speed and accuracy.
The use of keyboards having multiple characters on each key to reduce the overall size of the keyboard is known. Grover et al. in U.S. Pat. No. 5,818,437, whose disclosure is incorporated herein by reference, is among one of many publications which describes a reduced keyboard disambiguating computer, the keyboard having 12 keys, 9 of them labeled with numerous letters and other symbols. Grover describes, inter alia, how the keyboard disambiguating computer is used to process a keystroke sequence with a complete dictionary, and words which match the sequence of keystrokes are presented to the user in order of decreasing frequency of use. The user selects the desired word.
Other examples employing a keyboard having 12 keys include U.S. Pat. No. 6,307,548 and 549 to Flinchem et al. and King et al, respectively, whose disclosures are incorporated herein by reference, relate to a reduced keyboard disambiguating system having a keyboard with a reduced number of keys. A plurality of letters and symbols are assigned to a set of data keys so that keystrokes entered by a user are ambiguous. Due to the ambiguity in each keystroke, an entered keystroke sequence could match a number of words having the same number of letters. Each object is also associated with a frequency of use. Objects within the vocabulary modules that match the entered keystroke sequence are identified by the disambiguating system. Objects associated with a keystroke sequence that match the entered keystroke sequence are displayed to the user in a selection list.
The patents referenced hereinabove are related to a disambiguating input tool for handheld devices, known as the T9 system—initially developed by Tegics, San Diego, Calif. T9 has been embedded in many handset devices worldwide. Features of the T9 are described by Grover, Flinchem, and King, inter alia. The T9 system is simple and easy to implement. With the advent of touchscreen handset devices, the so-called XT9 keyboard was developed by Nuance, Boston, Mass.
Reference is now made to FIG. 1 which is a representation of a typical keypad 10, having individual keys 12. The idea behind the T9 system is simple and easy to implement. The keypad used has a total of twelve keys 12, among which eight are active keys, each of the eight keys having three or four characters 14 and a key-associated digit 16. In the specification and the claims which follow hereinbelow, the terms such as:“T9 keypad”; “T9 handset”; “8-key keyboard”; and “T9 arrangement” are used to mean a keypad configuration substantially as shown in FIG. 1.
In representing words using the handset of FIG. 1, a word or part of words in a dictionary can be labeled with the associated numbers. A word or sub-word composed of “n” characters is therefore labeled with “n” digits. When a user presses keys in a T9 handset to input a word, the sequence of keys he presses corresponds to a representative number, whose magnitude also reflects the number of keys pressed. After each keystroke, and until a key space or other disambiguation key is pressed, the system identifies in its dictionary for all the words or part of words associated with the equivalent number. The system sorts those words according to their frequency of use, starting with the highest frequency of use. As noted hereinabove, variants of this T9 algorithm are known in the art and they share a similar principle of disambiguation.
Suraqui (the Inventor of the present patent application) in U.S. Pat. No. 7,199,786, Kushler et al. in U.S. Pat. No. 7,098,896, and Zhai, in U.S. Pat. No. 7,251,367, whose disclosures are incorporated herein by reference, all discuss the concept of using a sliding motion to generate a bi-directional trajectory, thereby allowing the recognition of an inputted word. Methods and systems of inputting alphabetic text having a virtual keyboard on a touch-sensitive screen are also described. The virtual keyboard includes a set of keys where an each letter of alphabet is associated with at least one key, allowing a user to use the virtual keyboard with continuous contact of the touch sensitive screen. The user traces an input pattern for words by starting at or near the first letter in a decided word and then tracing through or near each letter in sequence. Then the system generates a list of possible words associated with the entered word/part of word and a list of candidate words is generated and presented to the user for selection.
While the prior art includes disambiguation methods most especially related to individual keystrokes and performing disambiguation by taking into account each individual pressed, there is a need for systems and methods to allow disambiguation not based on this method. The systems and methods should enable high-speed and accurate automatic disambiguating capabilities using text input in a relatively compact keyboard, thus allowing the use of a single disambiguation engine, whether the keyboard is virtual or “hard”.